view something hidden in a layer

I am trying to decipher an image (it's for an online game and I refuse to cheat for the answer!!)

I have a .psd image, that I have opened into layers - see the attached screenshot... It makes far more sense than the long-winded paragraph I just deleted!! All other layers were easy to deal with I just had to click on the eye to make them visible, but the one with the dotted box around it - I can't work out what to do..

So for this troublesome layer, I need to work out how to 'see' whatever is hiding in there. I have played around with lots of things, but the best I get is a white box if I remove the alpha channel.

I don't want to know what the other letters are, just how to find them (I am interested in learning how to do things, not just about the game, so I'm happy for explanations) =)

Eeek, sorry, I thought it might -- the u/n is mickey and p/word is mouse..

Basically, its the nature of the game for there to be something hidden To get to the next level I need to place a word in the url and there are clues within the level ie source code etc (its a rather fun and challenging game) - so I have some letters, and they don't spell anything, so there must be missing letters

I did the histogram thing for R, G, B, then RGB and alpha - I think there is something there for alpha at the very left in the black range (attached) -- this is where I'm a noob, I don't quite understand the terms you used.. I removed the alpha channel (I don't know why, just thought I'd try it), and now with threshold, I can see 4 little raised bits to the far right of the scale (attached).. But if I apply threshold, nothing is revealed. I am guessing these 'spikes' mean something (or I am hoping)..

Again, I love to know what I am doing and why, not just do it and make a lucky guess as to what works..